Bismuth and cement method of abandoning a well and means of real time verification of the bismuth and cement placement process

ABSTRACT

A method of abandoning a well, where the well is at least a length of tubing, and a first annulus outside the tubing, comprising the steps of puncturing a hole or holes in the tubing, the holes in the tubing giving access to the first annulus immediately outside the tubing, heating the inside of the tubing, depositing bismuth in proximity to the region inside the tubing which is heated, such that bismuth melts, the quantity of bismuth being sufficient that a first portion of the bismuth remains in the tubing, while a second portion of bismuth flows through the holes in the tubing into the first annulus, where it flows to the non-heated section allowing the bismuth to cool and solidify to form a plug in the tubing and the annulus

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application is the national stage entry of InternationalPatent Application No. PCT/GB2021/052193, filed on Aug. 23, 2021, andpublished as WO 2022/038387 A1 on Feb. 24, 2022, and claims priority toGreat Britain patent applications 2013067.0 filed on Aug. 21, 2020, and2014019.0 filed on Sep. 7, 2020, the disclosures of all of which arehereby incorporated by reference in their entireties.

BACKGROUND OF THE INVENTION

Over the past 20 years or so a large number of offshore structures havebeen constructed which are now or will soon be exhausted and will needto be abandoned. These offshore structures may comprise productionplatforms which are either steel or concrete structures resting on theseabed or floating platforms. Numerous conduits are connected to theseoffshore structures to carry the various fluids being gas, oil or wateretc., which are necessary for the production of oil and/or gas from thewell.

In abandoning a well, consideration has to be given to the potentialenvironmental threat from the abandoned well for many years in thefuture.

In the case of offshore structure there is usually no rig derrick inplace which can be used to perform the required well abandonmentprocedure. Therefore, it is typically necessary to install a new derrickor alternatively a mobile derrick can be positioned above the well. Thisrequirement adds considerable expense to the task of abandoning theoffshore well, compared to a land based well.

A typical production well will comprise a number of tubular conduitsarranged concentrically with respect to each. The method of abandoningthe well which is presently known in the art involves the separatesealing of each of the concentric conduits which requires a large numberof sequential steps.

In the abandonment method known in the art the first step is to seal thefirst central conduit usually by means of cement or other suitablesealant. The first annular channel between the first and second conduitsis then sealed and the first central conduit is then cut above the sealand the cut section is removed from the well.

The second annular channel between the second and third conduits is thensealed and the second conduit cut above the seal and the cut section isremoved from the well.

This process is repeated until all the conduits are removed. The numberof separate steps required is typically very large indeed and the numberof separate operations is five times the number of conduits to beremoved. This adds considerably to the cost of the well abandonment dueto the time taken and the resources required at the well head.

It is the purpose of the present invention to provide a method ofabandoning a well which avoids the disadvantageous and numerousoperations which are required by the existing known methods. This willgreatly reduce the costs of safely abandoning a well. It is a furtherobjective of the invention to provide a method of abandoning a wellwithout the requirement of a rig which involves significant expenseparticularly in subsea based wells.

SUMMARY OF THE INVENTION

According to the present invention there is provided a method ofabandoning a well, by using a tool to puncture holes in the tubing togain access to the annulus immediately outside it (annulus A)

According to a further aspect of the invention there is provided amethod of abandoning a well, by using a tool to puncture holes in thetubing and the casing outside it to gain access to the annulusimmediately outside it, and the annulus outside it (annulus A & B)

According to a further aspect of the invention, the hole could punctureby mechanical means

According to a further aspect of the invention, the hole could punctureby explosive means

According to a further aspect of the invention, the hole could punctureby a laser means

According to a further aspect of the invention, the hole could punctureby thermite plasma means

According to a further aspect of the invention, there is provided a toolto heat the inside of the tubing

According to a further aspect of the invention, there is provided a toolto heat the inside of the tubing using a thermite heat source

According to a further aspect of the invention, there is provided a toolto heat the inside of the tubing using a electrical heat trace heatsource

According to a further aspect of the invention, bismuth beads aredeposited on the heat source

According to a further aspect of the invention, bismuth beads areconveyed in a container above the heat source

According to a further aspect of the invention, bismuth beads aredeposited from surface using gravity

According to a further aspect of the invention the bismuth may be castonto the heating element and conveyed into the well by the heatingelement

According to a further aspect of the invention, bismuth beads meltaround the heat source, and flow out of the holes punched into thetubing.

According to a further aspect of the invention the bismuth solidifiesquickly as it drops down the outside of the tube, and eventually forms asolid platform in the annulus A

According to a further aspect of the invention, as the fluid isdisplaced in the annulus, the bismuth retains more heat and can conveythis heat to the casing outside it.

According to a further aspect of the invention, bismuth the fluidbismuth can enter the holes in the next casing and form a platform inthe annulus B

According to a further aspect of the invention, the column of bismuthprovides positive weight to enable all the annulus to fill evenly by theU Tube effect

According to a further aspect of the invention the well can havepermanent metal to metal seals placed at any desired depth in the well,in any number of annulus, provided the annulus can be penetrated.

According to a further aspect of the invention, when the heat source isremoved, as the steel tubulars cools they slightly contract, whereas asthe bismuth cools it expands, thereby energising the metal to metalseal.

According to a further aspect of the invention additional holes maybepunched into the tubing above the bismuth metal to metal seal and cementcirculated and positioned above the metal-to-metal seal inside thetubing and annulus A and annulus B

According to a further aspect of the invention a disposable chock (flowrestrictor) is deployed inside the tubing before cement is circulatedthus ensuring the controlled placement of the cement and eliminating Utubing which can have a serious detrimental effect of the final cementslurry placement

According to a further aspect of the invention the disposable choke canbe gravity deployed

According to a further aspect of the invention the disposable chokecould be deployed on a metal clad fibre optic cable.

According to a further aspect of the invention the choke area is formedby the OD of the tool and ID of the tubing in the well

According to a further aspect of the invention the disposable fibreoptic cable could provide distributed sensor feedback of the cementprocess

According to a further aspect of the invention the disposable fibreoptic cable could provide distributed temperature feedback of the cementprocess

According to a further aspect of the invention in combination withdisposable acoustic transmitters the disposable fibre optic cable couldprovide distributed acoustic feedback of the cement process, providingboth cement bond and cement density measurements

According to a further aspect of the invention at least one disposablebatterypowered acoustic transmitters could be combined with the metalclad fibre

According to a further aspect of the invention the tool housingcontaining the acoustic transmitter could include a heater and bismuthto make a metal-to-metal seal inside the housing once the cement has set

According to a further aspect of the invention the fibre optic cablecould have a shear release mechanism to enable the fibre optic cableabove the cement to be retrieved back to surface, so only a smallportion is consumed, and the rest can be used for a future operation

BRIEF DESCRIPTION OF THE DRAWINGS

The following is a more detailed description of an embodiment accordingto invention by reference to the following drawings in which:

FIG. 1 is a section side view of a well with the 1st operation of ametal-to-metal seal placed inside the tubing and first annulus outsidethe tubing.

FIG. 2 is a section side view of a well with the 2nd operation of ametal to metal seal placed inside the tubing and first annulus outsidethe tubing

FIG. 3 is a section side view of a well with the 3rd step of theoperation of a metal-to-metal seal placed inside the tubing and firstannulus outside the tubing.

FIG. 4 is a section side view of a well with the 4th step of theoperation of a metal-to-metal seal placed inside the tubing and firstannulus outside the tubing.

FIG. 5 is a section side view of a well with the final step of theoperation of a metal-to-metal seal placed inside the tubing and firstannulus outside the tubing.

FIG. 6 is a section side view of a well with the 1st operation of ametal-to-metal seal placed inside the tubing and first and secondannulus outside the tubing.

FIG. 7 is a section side view of a well with the 2nd operation of ametal to metal seal placed inside the tubing and first and secondannulus outside the tubing.

FIG. 8 is a section side view of a well with the 3rd step of theoperation of a metal-to-metal seal placed inside the tubing and firstand second annulus outside the tubing.

FIG. 9 is a section side view of a well with the 4th step of theoperation of a metal-to-metal seal placed inside the tubing and firstand second annulus outside the tubing.

FIG. 10 is a section side view of a well with the 5th step of theoperation of a metal-to-metal seal placed inside the tubing and firstand second annulus outside the tubing.

FIG. 11 is a section side view of a well with the final operation of ametal-to-metal seal placed inside the tubing and first and secondannulus outside the tubing.

FIG. 12 is a section side view of a well describing a 2^(nd) embodimentof the invention with the 1st operation of a metal-to-metal seal placedinside the tubing above the reservoir.

FIG. 13 is a section side view of a well shown in FIG. 12 with the 2ndoperation of a metal-to-metal seal placed inside the tubing above thereservoir.

FIG. 14 is a section side view of a well shown in FIG. 13 with the 3rdoperation of a metal-to-metal seal placed inside the tubing above thereservoir and the conveyance tool being pulled out of the hole

FIG. 15 is a section side view of a well with the 1st operation (settinga bridge plug) of a metal-to-metal seal placed inside the tubing andannulus A

FIG. 16 is a section side view of a well with the 2nd operation(puncturing the tubing) of a metal to metal seal placed inside thetubing and annulus A

FIG. 17 is a section side view of a well with the 3rd step of theoperation (placing molten bismuth in the tubing and annulus A) of ametal-to-metal seal placed inside the tubing and annulus A.

FIG. 18 is a section side view of a well with the 4th step of theoperation (placing molten bismuth in the tubing and annulus A) of ametal-to-metal seal placed inside the tubing and first annulus outsidethe tubing.

FIG. 19 is a section side view of a well with the 5th step of theoperation (placing molten bismuth in the tubing and annulus A) of ametal-to-metal seal placed inside the tubing and first annulus outsidethe tubing.

FIG. 20 is a section side view of a well with the 6th step of theoperation (perforating above the bismuth) of a metal-to-metal sealplaced inside the tubing and first annulus outside the tubing.

FIG. 21 is a section side view of a well with the 7th step of theoperation (installing a disposable choke and disposable sensor system toverify the cement plug placement) of a metal-to-metal seal placed insidethe tubing and first annulus outside the tubing.

FIG. 22 is a section side view of the well with detail A of FIG. 21 ,showing the disposable choke and disposable acoustic transmitter

FIG. 23 is a section YY plan view from FIG. 22 showing the flow chokearea created between the tubing ID and the disposable choke OD

FIG. 24 is a section XX plan view from FIG. 22 showing the flownon-choke area created between the tubing ID and the disposable choke OD

FIG. 25 is a calculation of the pressure drop for a single choke are fora typical cement density and placement flow rate and the pressure dropif 30 chokes are used

FIG. 26 is a section side view of the well with detail B of FIG. 21 ,showing the disposable fibre optic cable and disposable battery poweredacoustic transmitter before cementing

FIG. 27 is a section side view of the well with detail B of FIG. 21 ,showing the disposable fibre optic cable and disposable acoustictransmitter after cementing and the internals of the tool sealed withmolten bismuth

FIG. 28 is a section side view of a well with the final step of theoperation (cement placed on top of the bismuth plug with a disposablesensing system set in the cement) of a metal-to-metal seal placed insidethe tubing and first annulus outside the tubing.

FIG. 29 is a section side view of a well with the 1st operation (setbridge plug) of a 3rd type of hybrid metal-to-metal and cement sealplaced inside the tubing and annulus A and annulus B

FIG. 30 is a section side view of a well with the 2nd operation(perforate the tubing and casing) of a 3rd type of hybrid metal-to-metaland cement seal placed inside the tubing and annulus A and annulus B

FIG. 31 is a section side view of a well with the 3rd operation (deployheater and bismuth and place molten bismuth in tubing and annulus a andb) of a 3rd type of hybrid metal-to-metal and cement seal placed insidethe tubing and annulus A and annulus B

FIG. 32 is a similar view to FIG. 31 showing a further sequence in themolten bismuth placement of the 3rd operation.

FIG. 33 is a similar view to FIG. 32 showing a further sequence in themolten bismuth placement of the 3rd operation.

FIG. 34 is a similar view to FIG. 33 showing the molten bismuthplacement of the 3rd operation completed

FIG. 35 is a section side view of a well with the 4th operation(perforating above the bismuth plug and placing a disposable choke andsensor array in the tubing to monitor and verify the cement placement)of a 3rd type of hybrid metal-to-metal and cement seal placed inside thetubing and annulus A and annulus B

FIG. 36 is the completion of the 4th operation, cement plug placementcompleted in tubing and annulus A and B, and the fibre optic cabledisconnected from the disposable portion left in the cement plug.

DETAILED DESCRIPTION

Referring to FIGS. 1 to 5 there is shown a typical platform type wellarrangement, with a surface casing 1 combining as a riser 2 to thewellhead deck 3 of the platform 4. This is cemented in place from itsshoe 5 to the mud line 6.

Inside this is an intermediate size casing 7 which goes from thewellhead to just above the reservoir 8, in most cases the liner would becemented across the reservoir, however in this example the productiontubing 9 has been cemented 10 across the reservoir; the abandonmentmethod described herein is applicable to both instances. This has thenbeen perforated 11 to enable the reservoir fluids to flow to surface viathe production tubing.

At the end of commercial production, it is necessary to abandon thewell, traditionally this has required all the tubing and casing to beremoved from the well to enable long cement plugs to be placed insidethe resulting open hole. This is extremely expensive and time consuming.

The method shown will seal the well while requiring no material to beremoved from the well

The first seal 400 is required above the reservoir and is achieved usinga tool string and method described in complete detail inPCT/GB2021/051434

The next operations are the main focus for this application

Operation 1 is to run a bridge plug 30 to provide a base for thesubsequent operations

Operation 2 is to run a tubing hole puncturing tool 29 to make holes 31the tubing 9 above the bridge plug 30. Note that operation 1 and 2 couldbe combined into a single operation. Note that this tool and itsoperation is described in more detail in PCT/GB2021/051431

Operation 3 is to run a heating tool 28 to above the bridge plug. Thisheating tool could be thermite based or electrical heat element Notethat this tool and its operation is described in more detail inGB2017031.2

Operation 4 is to deposit bismuth beads 32 [the bismuth in the figuresis bit difficult to see—might be better if possible to illustrate it ina more visible way, perhaps with heavier hatching] onto the heatingelement from the housing above the heater, as the bismuth melts it flowsout of the perforations 31 and on the low side of the perforations belowthe heating tool, the bismuth quickly solidifies 33 eventually forming asolid base at the low side of the perforations

As the upper side of the tubing above the perforations is also adjacentto the heating tool the bismuth is still above its melting point, andthe bismuth has approximately ten times the specific gravity of thefluid in the well, the bismuth flows through the perforations 31 intothe annulus 35 to form an equal column of bismuth both inside the tubing34 and in the annulus 35

When the heating tool is removed, the bismuth balances while it is stillliquid the result is a solid plug of bismuth, both inside the tubing andinside the annulus of equal height. As it cools and returns to a solidstate it expands by approx. 3% and thus squeezes between the casing 7and the outside of the tubing 9, and the bismuth inside the tubingexerts an outward force on the internal surface of the tubing.

Referring to FIGS. 6 to 11 there is shown a sequence to seal the tubingID 37, annulus A 38 and annulus B 39.

Operation 1 is to run a bridge plug 40 to provide a base for thesubsequent operations.

Operation 2 is to run a tubing hole puncturing tool 41 to make holes 42in the tubing 9 and the casing 43 outside it above the bridge plug 40.Note that operation 1 and 2 could be combined into a single operation.Note that this tool and its operation is described in more detail inGB2015346.6, where it is necessary to puncture the casing beyond thetubing

Operation 3 is to run a heating tool 44 to above the bridge plug. Thisheating tool could be thermite based or electrical heat element, or acombination

Operation 4 is to deposit bismuth beads 45 onto the heating element 44,as the bismuth melts it flows out of the perforations 42 and on the lowside of the perforations, the bismuth quickly solidifies 46 eventuallyforming a solid base in the annulus A 47. As more bismuth displaces thefluid in the annulus, more heat is transferred to the casing 48 outsideit. As the heating is transferred to the bismuth in the first annulus Aits flows into annulus B 49 where it quickly solidifies and forms asolid base 50 on the low side of the perforations for the liquid bismuthto be supported on top of it.

The liquid bismuth is between approximately 7-10 times the density ofthe liquid in annulus A and B. and provides the hydrostatic force todisplace the liquid bismuth into the annulus A and B, as more bismuthflows into the annulus A and B more heat is transferred to the annulus Aand B, resulting in easier flow of the bismuth into both annuli,resulting in the top level of the molten bismuth approximatelyequalising in height across the tubing ID and annuli in a similar way tothe previously described steps.

The result is a solid plug of bismuth, both inside the tubing 52 andinside the annulus A 53 and the Annulus B 54. As it cools and returns toa solid state it expands by approx. 3% and thus squeezes between thesurface casing 1 and the intermediate casing 7, and intermediate casing7 and the outside of the tubing 9, and the bismuth inside the tubingexerts an outward force on the internal surface of the tubing 9.

Referring to FIGS. 12 to 14 there is shown a typical platform type wellarrangement, with a surface casing 101 combining as a riser 102 to thewellhead deck 103 of the platform 104. This is cemented in place fromits shoe 105 to the mud line 106.

Inside this is an intermediate size casing 107 which goes from thewellhead to just above the reservoir 108, in most cases the liner wouldbe cemented across the reservoir, however in this example the productiontubing 109 has been cemented 110 across the reservoir. This has thenbeen perforated 111 to enable the reservoir fluids to flow to surfacevia the production tubing.

As previously discussed, at the end of commercial production, it isnecessary to abandon the well, traditionally this has required all thetubing and casing to be removed from the well to enable long cementplugs to be placed inside the resulting open hole. This is extremelyexpensive and time consuming.

The method shown will seal the well while requiring no material to beremoved from the well

Operation 1 is to run a bridge plug 120 to provide a base for thesubsequent operations.

Operation 2 is to run a heating tool 121 on a wireline 170 to above thebridge plug. This heating tool could be thermite based or electricalheat element, or a combination Note that this tool and its operation isdescribed in more detail in PCT/GB2021/051434

Operation 3 is to deposit bismuth beads 122 onto the heating element, asthe bismuth melts it forms a molten mass around the heating tool.Temperature sensors in the heating tool will provide feedback that thebismuth is at the uniform temperature and the heating tool can beremoved 123 back to surface. On cool down the bismuth solidifies andforms a solid metal to metal seal 124 above the bridge plug

Referring to FIGS. 15 to 28 ;

Operation 1 is to run a bridge plug 130 to provide a base for thesubsequent operations

Operation 2 is to run a tubing hole puncturing tool 129 to make holes131 the tubing 109 above the bridge plug 130

Operation 3 is to run a heating tool 128 to above the bridge plug. Thisheating tool could be thermite based or electrical heat element, or acombination of both.

Operation 4 is to deposit bismuth beads 132 onto the heating element, asthe bismuth melts it flows out of the perforations and on the low sideof the perforations, below the heating element the bismuth quicklysolidifies 133 eventually forming a base 172.

As the upper side of the perforations is adjacent to the heating toolthe bismuth is still above its melting point, the bismuth withapproximately 10 times the specific gravity of the fluid in the well,flows through the holes 131 to form an equal column of bismuth bothinside the tubing 134 and in the annulus 135

The bismuth below the perforation 172 is sufficient to form a base butdoes not have a good pressure containment quality. The bismuth above theperforation and which was a fully molten mass forms a very high-qualitymetal to metal seal and hence an excellent pressure barrier (134,135).

The result is a solid plug of bismuth, both inside the tubing and insidethe annulus. As it cools and returns to a solid state it expands byapprox. 3% and thus squeezes between the casing 107 and the outside ofthe tubing 109, and the bismuth inside the tubing exerts an outwardforce on the internal surface of the tubing

Operation 5 is to is to run a tubing hole puncturing tool 173 to makeholes 300 in the tubing 109 above the bismuth plug 134 inside thetubing.

Operation 6 is to install a disposable choke 200 on a metal clad fibreoptic cable 201, the fibre optic cable provides real time distributedsensing in its simplest form distributed temperature, so will verify thecement setting process in the tubing 302 and the annulus 301 and willalso accurately show the exact top of cement 303. The choke is a hollowtube 202, with the metal clad fibre attached to its nose 203. Inside thenose could also be a battery powered acoustic transmitter 204 and thefibre optic cable can also act as an acoustic receiver so it could alsoprovide a cement bond and cement density measurement during and at theend of the cement setting process. Disposable transmitters 205 could bedistributed along the metal clad fibre. The inside of the acoustictransmitter will be bismuth 210 and a nichrome wire heating element wire304 embedded inside the bismuth, the lithium battery 211 which is usedto power the acoustic transmitter 205 also after a set period of time(24-48 hrs) heats up the bismuth, which melts and forms a solid barrier212 inside the tool housing 213.

On the outside of the choke tube 202 are discs 213, when the OD of thedisc 306 is adjacent to the tubing ID 305 it provides the flowrestriction area 206, to ensure the flow path does not get plugged, itis relatively speaking quite a large area 214, in this case 2 sq inches(13 cm²), which generates about 20 psi pressure drop at the flow rateand density of a typical plug placement, by using many of the chokediscs 213 a very significant back pressure is generated which ensuresthe controlled placement of the cement slurry 208 described below.

Operation 6 is to circulate cement down the tubing, and into the annulusto form a balanced cement plug 136 inside the tubing and annulus 135.

Referring to FIGS. 29 to 36 there is shown a sequence to seal. thetubing ID 137, annulus A 138 and annulus B 139.

Operation 1 is to run a bridge plug 140 to provide a base for thesubsequent operations.

Operation 2 is to run a tubing hole puncturing tool 141 to make holes142 in the tubing 119 and the casing 143 outside it above the bridgeplug 140

Operation 3 is to run a heating tool 144 to above the bridge plug. Thisheating tool could be thermite based or electrical heat element

Operation 4 is to deposit bismuth beads 145 onto the heating element, asthe bismuth melts it flows out of the perforations 142 and on the lowside of the perforations, the bismuth quickly solidifies 146 eventuallyforming a solid base in the annulus A 147. As more bismuth displaces thefluid in the annulus, more heat is transferred to the casing 148 outsideit. As the heating is transferred to the bismuth in the first annulus Aits flows into annulus B 149 where it quickly solidifies and forms asolid base 150 for the liquid bismuth to be supported on.

The liquid bismuth is between 7-10 times the density of the liquid inannulus A and B. The column in the tubing 151 provides the hydrostaticforce to displace the liquid bismuth in the annulus A and B, as morebismuth flows into the annulus A and B more heat is transferred to theannulus A and B, resulting in easier flow of the bismuth into bothannuli.

The result is a solid plug of bismuth, both inside the tubing 152 andinside the annulus A 153 and the annulus B 154. As it cools and returnsto a solid state it expands by approx. 3% and thus squeezes between thesurface casing 101 and the intermediate casing 107, and intermediatecasing 107 and the outside of the tubing 109, and the bismuth inside thetubing exerts an outward force on the internal surface of the tubing109.

Operation 5 is to run a tubing hole puncturing tool to make holes 160 inthe tubing 109 and the casing 143 outside it above the bismuth plug setin operation 4.

A disposable choke 200 is deployed on a section of disposable metal cladfibre optic cable 201 with also disposable distributed battery poweredacoustic transmitters 204, as described earlier are to ensure thecontrolled placement of cement slurry and then to verify the quality ofcement and cement setting process by a combination of temperature andacoustic measurements.

Then cement slurry can be circulated down the tubing into the annulus Aand annulus B to form a balanced plug 161. Alternatively, it could becirculated down one of the annuli to minimise the effect of U tubing ifno choke is used.

After monitoring the cement temperature, at a suitable time after thecement operation, the disposable portion of the metal clad fibre opticcable 162 can be left in the well, and a shear release 163 can ensurethe reliable separation of the metal clad fibre optic cable, and therecovered metal clad fibre 164 can be reused on a future job.

1. A method of abandoning a well, the well comprising at least a lengthof tubing, and a first annulus outside the tubing, comprising:puncturing a hole or holes in the tubing, the holes in the tubing givingaccess to the first annulus immediately outside the tubing; heating theinside of the tubing; and depositing bismuth in proximity to the regioninside the tubing which is heated, such that bismuth melts, the quantityof bismuth being sufficient that a first portion of the bismuth remainsin the tubing, while a second portion of bismuth flows through the holesin the tubing into the first annulus, where it flows to the non-heatedsection allowing the bismuth to cool and solidify to form a plug in thetubing and the annulus.
 2. A method according to claim 1 wherein thewell further comprises a second tube concentric with the length oftubing, and a further annulus outside the second tube, and including thesteps of puncturing a hole or holes in the second tube, the holes in thetubing giving access to the further annulus immediately outside thesecond tube the quantity of bismuth being sufficient that a firstportion of the remains in the tubing, while a second portion of bismuthflows through the holes in the tubing into the first annulus, while athird portion of bismuth flows through the holes in the second tube intothe further annulus.
 3. (canceled)
 4. A method of abandoning a wellaccording to claim 1, wherein the holes are punctured by mechanicalmeans.
 5. A method of abandoning a well according to claim 1, whereinthe holes are punctured by explosive means.
 6. A method of abandoning awell according to claim 1, wherein the holes are punctured by a lasermeans
 7. A method of abandoning a well according to claim 1, wherein theholes are punctured by thermite plasma means
 8. A method of abandoning awell according to claim 1, wherein the inside of the tubing is heatedusing a thermite heat source
 9. A method of abandoning a well accordingto claim 1, wherein the inside of the tubing is heated using anelectrical heat trace heat source
 10. A method of abandoning a wellaccording to claim 1, wherein the bismuth is deposited in the forms ofbismuth beads deposited on the heat source.
 11. A method of abandoning awell according to claim 10, wherein the bismuth beads are conveyed in acontainer above the heat source.
 12. A method of abandoning a wellaccording to claim 10, wherein the bismuth beads are deposited fromsurface using gravity
 13. A method of abandoning a well according toclaim 1, wherein the bismuth is cast onto the heating element andconveyed into the well by the heating element.
 14. A method ofabandoning a well according to claim 1, including the steps ofpuncturing additional holes into the tubing above the region the bismuthhas solidified circulating cement inside the tubing and a first annulusand/or further annuli above the solidified bismuth.
 15. A method ofabandoning a well according to claim 14, wherein there is included thestep of deploying a disposable choke inside the tubing before cement iscirculated to restrict the flow of cement to ensuring the controlledplacement of the cement.
 16. A method of abandoning a well according toclaim 15, wherein the disposable choke is gravity deployed.
 17. A methodof abandoning a well according to claim 15, wherein the disposable chokeis deployed on a metal clad fibre optic cable.
 18. A method ofabandoning a well according to claim 15, wherein the choke area isformed by the OD of the chokeand ID of the tubing.
 19. A method ofabandoning a well according to claim 14 wherein a disposable fibre opticcable provides distributed sensor feedback of the cement process.
 20. Amethod of abandoning a well according to claim 19 wherein the disposablefibre optic cable provides distributed temperature feedback of thecement process.
 21. A method of abandoning a well according to claim 19wherein at least one disposable battery powered acoustic transmitters iscombined with the metal clad fibre optic cable.
 22. A method ofabandoning a well according to claim 21 wherein the disposable fibreoptic cable in combination with disposable acoustic transmitters thedisposable fibre optic cable provides distributed acoustic feedback ofthe cement process, providing both cement bond and cement densitymeasurements.
 23. A method of abandoning a well according to claim 19wherein the tool housing containing the acoustic transmitter couldinclude a heater and bismuth to make a metal-to-metal seal inside thehousing once the cement has set.
 24. A method of abandoning a wellaccording to claim 19 wherein the fibre optic cable has a shear releasemechanism to enable the fibre optic cable above the cement to beretrieved back to surface.
 25. A choke according to claim 15, the chokecomprising a hollow tube having discs disposed long the length of theinside of the hollow tube, such that the tube allows a through flowwhich is restricted by the discs, the hollow tube being suspended by afibre optic cable terminating at the lower end of the hollow tube, thefibre optic cable including sensors.
 26. A choke according to claims 25wherein the sensors include acoustic sensors, and acoustic transmittersare included in the choke.